Closed cell sponge weatherstrips have been the standard for years to seal vehicle closures against the passage of air and moisture. The weatherstrip attaches to the vehicle body or closure around the opening (e.g. door or trunk opening). The weatherstrip preferably includes a bulbular or tubular section that is designed to provide an interference fit between the closure and body, and a mounting section to secure the weatherstrip in place. Generally, the greater the interference, the better the sealing function is obtained.
A tight seal is important in order to isolate passengers from inclement weather conditions and also to reduce wind noise as the vehicle passes through the air. The tighter the degree of interference of the weatherstrip between the closure and closure frame, however, the greater the effort is required to close the closure.
Another consideration of a higher degree of interference is the annoying problem of "compression shock". The rapid closing of a door on an otherwise closed vehicle often results in a trapping of air and a momentary air compression in the passenger compartment. This compression shock not only further increases the closing effort required, but also causes an unpleasant feeling to the passengers.
Until recently, attempts to reduce door closing effort resulted in reduced sealing efficiency. Conversely, early attempts to improve sealing resulted in a need for excessive closing effort. Neither extreme is favored by consumers. Thus, in the past, automotive engineers found it necessary to compromise these apparently conflicting engineering requirements, with the best designs carefully balancing the relationship between sealing and closing effort. Of course, any solution that is the result of compromise fails to provide either the most desired closing effort or the best sealing. Accordingly, a significant need existed for a system that could independently address the requirements and provide better sealing while also maintaining closing effort at a desired level.
One of the best approaches to date and one that effectively addresses the conflicting concerns for improved sealing and reduced closing effort is set forth in U.S. Pat. No. 4,761,917 entitled "Deflatable Weatherstrips", issued Aug. 9, 1988, of which I am a co-inventor. In this patent a system is described that provides both improved sealing and reduced closing effort of vehicular closures by utilizing the concept of deflatable weatherstrips. With this approach, a deflatable sealing member forms a weatherstrip to seal the opening in the vehicle body around the closure. The sealing member is connected to a vacuum source such as a bellows pump mounted in the hinge area of the closure. When the closure is closed, the sealing member is deflated so as not to engage in an interference fit between the door and closure. In this manner, closing effort is reduced and compression shock substantially eliminated. Following closing, the sealing member is vented to ambient pressure. This causes the sealing member to expand by built-in resilient memory to provide firm sealing engagement with increased resilient interference between the closure and the body. Advantageously, better sealing is thereby provided. Accordingly, wind noise is reduced and passenger comfort is enhanced.
Space limitations and design constraints particularly in compact automobile models, however, make it very difficult to mount a bellows pump in position in the hinge area between the closure and the frame. U.S. Pat. No. 4,805,347 issued Feb. 21, 1989, entitled Bellows System for Deflating Weatherstrips of which I also am the inventor, addresses this problem by providing a closure sealing mechanism wherein a bellows pump, actuated by closure movement, is specially adapted for convenient mounting in a space anywhere on the closure or the frame adjacent but spaced from the hinge area. While this improved system may be adapted for utilization in some compact automobiles where insufficient space exists in the hinge area to utilize the original design of U.S. Pat. No. 4,761,917 certain vehicle designs still do not have the necessary space to effectively incorporate this design.
Additionally, since both of these prior art systems include an individual deflation or vacuum unit for each sealing member, there is a duplication of components that adds significantly to system cost, while also potentially increasing maintenance requirements. Also, since the vacuum volume generated by each bellows is necessarily limited, there is a lack of reserve vacuum, which can present a problem in terms of attaining full deflection of the sealing member. This may occur where the closure is opened only partially and then closed.
The present invention addresses these problems by providing a centralized vacuum source that may be selectively connected to a plurality of deflatable sealing members. Thus, advantages in packaging convenience in the vehicle, cost over the prior art and improved operation are provided. The centralized vacuum source incorporating the desired capacity to assure appropriate reserve, may be mounted at any convenient location within the vehicle body including the engine compartment. Hence, it may be adapted for use for any desired number of closures and in substantially any vehicle including compact and subcompact models.
It should also by appreciated that the operational problems resulting from small system leaks that have plagued previous centralized systems are minimized by the present invention. This is done by providing a means to actuate the vacuum source only upon the closing movement of the closure. Thus, negative pressure need only be maintained for a very short period of time (i.e. the pressure is provided for only the one or two seconds during door closing). At all other positions of the closure, the vacuum is blocked and the weatherstrip is opened to the atmosphere to allow expansion to full cross-section by built-in resilient memory. As a result, the desired tight seal is provided.